Voice delivered using the Internet Protocol (IP), or Voice over IP (VoIP) is a set of facilities for managing the delivery of voice information using IP packets. In general, this VoIP is used to send voice (and video) information in digital form in discrete data packets (i.e., IP packets) over data networks rather than using traditional circuit-switched protocols used on the public switched telephone network (PSTN). VoIP is used on both wireless and wired data networks.
There are many problems associated with using VoIP. One problem is that existing VoIP protocols (e.g., H.323, H.324, SIP, etc.) typically require a sequence of messages (exchanging capabilities, checking availability, registering with servers, etc.) before voice communications can begin—thus requiring rather large call setup times. These protocols were primarily designed to simulate single user PSTN connections between a network endpoint and either another network end point or a PSTN endpoint.
Another problem is that communicating with multiple user's simultaneously (i.e., N-way conferencing) using VoIP typically requires additional messaging, additional infrastructure components and a separate IP session with each user. If the number of user's to communicate with is large, the call setup time and bandwidth utilization can quickly become unmanageable.
Another problem is that Traditional Land Mobile Radio systems (e.g., EDACS, Astra, LMR, etc.) provide fast setup half-duplex conferencing voice communications (i.e., group calls) through a proprietary wireless voice communications system. These systems are traditionally circuit switched and design for wide area coverage. See e.g., U.S. Pat. No. 6,330,224, entitled “System for digital radio communication between a wireless lan and a PBX,” that issued to Swartz et al. These systems are expensive and not conducive to many enterprise environments and not easily usable for VoIP N-way conference calls.
Thus it is desirable to quickly and efficiently set-up N-way conference calls using VoIP.